High-speed Brushless DC Motor Research Articles

Analysis of interior rotor for high-speed brushless DC motor using finite element method

<span lang="EN-US">The permanent magnet of brushless DC (BLDC) motor is ideally suited for high-speed application due to its superior performance and efficient as compared to other types of electrical motors. However, to operate in high-speed operation, the rotors that hold the magnet must be able to withstand high centrifugal force. Due to that, the main objective of this project is to design and develop the suitable rotor for high-speed BLDC motor through the finite element method (FEM) Ansys Maxwell modeling software. In addition, this project is also carried out to determine the ability of the modeled software to reach the high-speed performances in terms of cogging torque and induce voltage. In this project, the selected BLDC motor was fabricated and measured experimentally. The result showed that the designed rotor can achieve speed of almost 14,500 rpm.</span>

High-Dynamic and Low-Cost Sensorless Control Method of High-Speed Brushless DC Motor

Sensorless control is an effective measure to improve reliability and reduce cost for the brushless DC motor (BLDCM). However, the performance is generally related to the cost and complexity of the system, making it difficult for engineering applications. Therefore, this paper proposes a high-dynamic and low-cost sensorless control method for high-speed BLDCMs using the rich built-in resources of the digital signal processor (DSP). Firstly, a variable relating to the commutation moment is constructed and detected, which is not affected by modulation noise. Then, a detailed commutation process is presented based on the relationship between the back electromotive force (back-EMF) integral and the commutation point. Moreover, an integral prediction method is proposed by linearizing the back-EMF to cope with the effect of discrete sampling on commutation accuracy. Finally, experimental tests are performed on a magnetically suspended control moment gyroscope (MSCMG), which verifies the effectiveness of the proposed high-dynamic and low-cost sensorless control method.

A Commutation Optimization Strategy for High-Speed Brushless DC Drives With Voltage Source Inverter

The control performance of Hall sensor-based high-speed brushless dc (BLdc) motor drives depends heavily on the accuracy of Hall sensor signals. Due to the existence of Hall signal errors, the system may operate under unbalanced conditions that will lead to asymmetric currents and high-torque ripple. For high-speed BLdc drive, using voltage source inverter (VSI) with the pulsewidth modulation (PWM) technique will also lead to PWM update delay that causes inaccurate commutation. In this article, two Hall signal errors, i.e., misaligned and uneven Hall signal errors, are investigated and a Hall signal balancing strategy is developed to detect Hall signal errors and regenerate balanced Hall signals. A novel PWM generation scheme is then proposed to eliminate the PWM update delay when using traditional VSI. Both simulation and experiment results have verified the effectiveness of the proposed strategy.

An internal power angle control strategy for high-speed sensorless brushless DC motors

High-speed Brushless DC Motors (BLDCMs) usually adopt a sensorless control strategy and operate in three-phase six-state drive mode. However, the sampling errors of the rotor position and the driving method increase the Internal Power Angle (IPA), resulting in a decrease in the efficiency of the system. Conventional IPA reduction strategies are either sensitive to motor parameters, or ignore diode freewheeling during the commutation process, or require additional current sensors. In this paper, a new strategy to reduce the IPA is proposed. Firstly, a Zero-Crossing Point (ZCP) detection method for the back-EMF without filter is proposed to reduce the sampling errors of the rotor position. Secondly, the relationship between the non-energized terminal voltage and the ZCP of the corresponding back-EMF is analyzed. The non-energized terminal voltage that has completed the diode freewheeling is divided into two triangles by half of the bus voltage. When the IPA is suppressed, the areas of the two triangles are equal. Thirdly, an advanced angle for reducing the IPA is obtained through a PI regulator which can eliminate the deviation between the two areas. Finally, both a simulation model and an experimental circuit are built to verify the proposed control strategy.

Fault Diagnosis of High-Speed Brushless Permanent-Magnet DC Motor Based on Support Vector Machine Optimized by Modified Grey Wolf Optimization Algorithm

With the development of reliability theory, people realized that “absolutely reliable” machines could not be made. With its incomparable advantages, the high-speed permanent-magnet brushless DC motor is usually used in the symmetrical structure of high-speed operation working systems, which at present are widely used in aerospace and other fields. The structure of the manufacturing process involves a strict processing, but in the process of work failure could still occur. No matter what field the high-speed permanent magnet brushless DC motor is applied to, it is very important to identify states and run fault diagnosis, which is of great significance to maintain the reliability of the motor and its working system. In this study, the fault diagnosis method of a high-speed permanent-magnet brushless DC motor is studied, and a combination model of modified gray wolf optimization algorithm (MGWO) and support vector machine (SVM) have been proposed for the motor fault diagnosis research. Based on the traditional gray wolf optimization (GWO) algorithm, the optimization performance of the algorithm is improved by initializing the population through a tent map and introducing a sine wave dynamic adaptive factor. Then the modified algorithm is used to optimize the internal parameters of SVM to improve the diagnostic accuracy of the model. Through the signal acquisition test, the current signals under different fault states and faultless states were collected, and the current signal data set required for the experiment is obtained. The experimental result showed that, compared with GWO or sailfish optimization (SFO) optimized SVM models, Extreme learning machine and Back Propagation neural network classical classification models, the fault diagnosis accuracy of the proposed model is the highest, proving the excellent classification performance and good robustness of the MGWO-SVM model.

Virtual Third Harmonic Back EMF-Based Sensorless Drive for High-Speed BLDC Motors Considering Machine Parameter Asymmetries

This article investigates the virtual third harmonic back electromotive force (EMF)-based sensorless drive method for high-speed brushless dc (BLDC) motors. Conventional zero-crossing point (ZCP) detection methods of virtual third harmonic back EMF require hardware low-pass filters and voltage comparators, causing serious phase lag. To avoid the undesired phase lag of hardware, the proposed method employs algorithmic oversampling technique to reconstruct the envelope of virtual third harmonic back EMF. Besides, the number of sampling points is dynamically adjusted according to the pulsewidth modulation duty ratio to guarantee the accuracy of ZCP detection. In addition, the influence of asymmetric motor parameters, i.e., phase resistance and inductance, on sensorless commutation is analyzed in depth. With asymmetric impedances, ZCPs of virtual third harmonic will deviate from their ideal positions. Consequently, the commutation events, which are searched based on ZCPs, will also be triggered at inaccurate positions and then the control performance will be deteriorated. In order to suppress the negative influence, a novel phase compensation method is proposed. All the theoretical analyses are validated by experiments at a 60 000 r/min BLDC drive platform.

Expansion of Operating Speed Range of High-Speed BLDC Motor Using Hybrid PWM Switching Method Considering Dead Time

In vehicle electrical systems with limited battery power, the output torque and speed of high-speed brushless DC (BLDC) motors can decrease due to unstable and reduced supply voltage or manufacturing errors in the motor back electromotive force (EMF). This paper presents a method that can guarantee the output performance of an inverter through a control algorithm without a separate power supply system and DC-link voltage increase. The proposed control algorithm can increase the output torque and speed of a high-speed BLDC motor by using appropriate selection and change of the inverter’s pulse width modulation (PWM) control method. In this paper, the operation and electrical characteristics of various PWM methods of BLDC motors are analyzed, and the optimal PWM method for improving the control performance of high-speed BLDC motors is presented. In addition, the relationship between the switching frequency, dead time, and voltage utilization was mathematically analyzed. Based on the results of this analysis, the proposed control algorithm automatically changes the PWM switching mode at the point where the output torque and speed need to be extended. The effectiveness and feasibility of the control method proposed in this paper is verified through the experimental results on the designed and manufactured high-speed BLDC motor system for vehicles.

Hybrid PWM Control for Regulating the High-Speed Operation of BLDC Motors and Expanding the Current Sensing Range of DC-link Single-Shunt

This study developed a hybrid pulse width modulation (PWM) control method intended for use in a high-speed brushless dc (BLDC) motor drive system that uses DC-link single-shunt current measurement. The method is designed to regulate rapid operation and expand the current sensing range of the aforementioned system and measurement, respectively. The operating characteristics of most typical PWM methods for BLDC motors were analyzed, after which, a PWM approach suitable for high-speed operation was identified. On the basis of the selected approach, the measurable range of DC-link single-shunt current was examined mathematically to determine a PWM method that is advantageous for current sensing. The results of the two analyses were used as guidance in formulating the proposed hybrid PWM control algorithm. Finally, the PWM method put forward in this work was verified through experimentation.

Reduction of Rotor Harmonic Eddy-Current Loss of High-Speed PM BLDC Motors by Using a Split-Phase Winding Method

Low-order harmonic currents in high-speed permanent magnet brushless dc (PM BLDC) motors cause large rotor eddy-current loss, resulting in high temperature rise and even overheating in the rotors, thus their application in the field of high-speed drive is limited. The rotor eddy-current loss can be reduced by using a split-phase winding method. In this paper, various time–space orders of harmonic eddy-current losses in the rotors of the PM motors with and without split-phase winding are quantified. The calculated results indicate that the rotor harmonic eddy-current losses generated by the low-order harmonic currents, which inherently exist in PM BLDC motors, are greatly reduced. Furthermore, associated with the characteristics of harmonic currents of PM BLDC motors, the mechanism of drastically reducing the rotor harmonic eddy-current loss of high-speed PM motors by using the split-phase winding method is revealed and experimentally validated.

Adaptive Threshold Correction Strategy for Sensorless High-Speed Brushless DC Drives Considering Zero-Crossing-Point Deviation

This article investigates the influence of two nonideal factors on zero-crossing-point-detection-based sensorless control of high-speed brushless dc (BLDC) motor, i.e., asymmetric machine parameters and the resistance tolerance of back electromotive force (EMF) measurement circuit. Influenced by the machine parameter asymmetry, the back EMF envelopes will shift horizontally from its ideal position. Furthermore, the acquisition accuracy of back EMF is limited by the resistance tolerance of measurement circuit. Inaccurate acquisition of back EMF will result in vertical deviation of the envelopes. These two nonideal factors decrease the commutation accuracy and deteriorate the control performance. In order to suppress the commutation errors, an adaptive threshold correction strategy, including horizontal and vertical corrections is proposed for eliminating the influence of these two nonideal factors, respectively. In addition, the proposed correction method does not depend on any parameters of the machine or the measurement circuit. Finally, the theoretical analysis and the proposed correction method are verified by experiment on a 54 000 r/min high-speed BLDC drive platform.

High-speed Permanent Magnet Brushless DC Motors, Properties and Prospective Applications

Wydawnictwo SIGMA-NOT wydaje czasopisma fachowe informujące swoich czytelników o najnowszych osiągnięciach naukowych i nowoczesnych rozwiązaniach technicznych w Polsce i na świecie, popularyzuje problemy techniczne oraz poszerza wiedzę i kulturę techniczną.

Investigation of Systematic Efficiency in a High-Speed Single-Phase Brushless DC Motor Using Multi-Physics Analysis for a Vacuum Cleaner

This paper discusses systematic efficiency considering the efficiency of both a motor and airflow in an inverter-driven single-phase brushless direct-current (BLDC) motor with two different lamination designs for a cordless vacuum cleaner. In other words, multi-physical lamination design has to be conducted, and hence, the shape and placement of a whole electromagnetic structure are investigated in terms of a tradeoff between the electrical and mechanical efficiencies. In this paper, a single-phase BLDC motor for cordless vacuum cleaners is designed to satisfy starting and continuous torques by means of asymmetric air gap, and fluid analysis is performed to determine which shape of a single-phase BLDC motor has better system efficiency. The prototype of a single-phase BLDC motor has been tested, and the speed of the operation is ranged from 84468 r/min up to the rated speed of 100020 r/min. The motor efficiency of 94.7% has been measured to verify a good match with the estimated efficiency of 94.5%.

Sensorless Startup Strategy for a 315-kW High-Speed Brushless DC Motor With Small Inductance and Nonideal Back EMF

This paper presents a novel sensorless startup strategy for a 315-kW high-speed magnetic suspension brushless dc (BLDC) motor with small inductance and nonideal back electromotive force (EMF). Two key strategies on the sensorless startup strategy of the BLDC motor are presented: First, small current startup strategy for the high-speed BLDC motor with small inductance; and second, self-adaption control strategy to compensate the commutation error for the BLDC motor with nonideal back EMF in the startup stage. A hybrid pulsewidth modulation strategy based on the load torque is proposed to limit the startup current. An optimal motor startup curve based on the system parameters is presented, and a self-adaption control strategy is proposed to solve the synchronous switching problem. The effectiveness and feasibility of the proposed method is verified by a series of experiments on the 315 kW, 20 000 r/min magnetic suspension blower platform.

Design of Sensor less Sliding-Mode BLDC motor Speed regulator using Class of Uncertain Takagi-Sugeno Nonlinear Systems

Current Research Brushless dc motor (BLDC) is very popular in wide variety of applications. In comparison to conventional dc motor, the brushless dc motor having electronic commutator rather than mechanical commutator, so it is more reliable than the dc motor. BLDC motors are commonly used in high end white goods (refrigerator, washing machine, dish washer etc.), high end pump applications which require higher reliability and efficiency. This paper proposed a new method for sensor less speed control of high-Speed brushless Dc motors with higher reliability of the motor. The sensor less BLDC motor based on back EMF sensing and a rotor position angular detection value. The Nonlinear characteristics of Sensor less BLDC motor analyzed using (TZ) fuzzy model in MATLAB. Simulated Results shows proposed control method superior than conventional controllers.

A PLL-Based Novel Commutation Correction Strategy for a High-Speed Brushless DC Motor Sensorless Drive System

Commutation error degrades the operating performance of a high-speed permanent magnet brushless dc motor (BLDC) sensorless drive significantly. It is caused by different kinds of nonideal factors such as low-pass filters (LPFs), digital control delay, and other units in a control loop. This paper analyzes the commutation error caused by different kinds of nonideal factors and points out that the total commutation error is substantially equivalent to the error of an internal power factor (IPF) angle of the BLDC motor. The purpose of the commutation correction in this paper is to regulate the IPF angle to zero. A novel phase-lock loop (PLL)-based commutation correction strategy is proposed and designed in detail in this paper. The proposed PLL consists of a novel PM flux linkage based phase discriminator to detect the IPF angle, an LPF, and an autophase regulator (APR). The function of the proposed PLL is to lock the IPF angle to a reference value. Compared to the conventional scheme, the greatest advantage of the proposed scheme is that the proposed PLL is robust to any kind of phase delay caused by nonideal factors in the control loop, and it is quite important for a high-speed motor drive. Both simulation and experimental results verify the effectiveness and superiority of the proposed correction strategy.

Comparative Performance Analysis of Reference Voltage-Controlled Pulse Width Modulation for High-Speed Single-Phase Brushless DC Motor Drive

The recent advancements in power switching device material and manufacturing technology have enabled the design of highly efficient and compact high-speed motor direct drives. The use of high-switching frequency pulse width modulation in these drives provides speed and torque control capabilities and it can also serve as an effective phase current shaping method for torque ripple minimization. This paper builds upon the previous paper introducing a torque ripple minimization technique for gallium nitride high-electron mobility transistor-based high-speed single-phase brushless dc motor drive. It presents an in-depth performance analysis in comparison with the conventional high-speed control techniques. Four different high-speed control techniques are implemented and tested to quantify the maximum speed, efficiency, torque ripple, and vibration. The vibration of the motor drive is measured using a microelectromechanical systems accelerometer with a ferroelectric random access memory for high-speed data acquisition with the maximum bandwidth of 1 kHz.

Sensorless Control Strategy of a 315 kW High-Speed BLDC Motor Based on a Speed-Independent Flux Linkage Function

A sensorless control strategy of a high-speed 315 kW brushless dc (BLDC) motor based on a speed-independent flux linkage function is proposed in this paper. It addresses the two key challenges on the sensorless control of high-speed BLDC motor: proposing a speed-independent flux linkage function to ensure reliable operation in the low-speed range, and presenting correction strategy to provide accurate commutation points in the high-speed range. First, the sensorless detection circuit model of a 315 kW BLDC motor is discussed. The analysis shows that the speed-independent flux linkage function is really suitable for BLDC motor sensorless control strategy in the low-speed range. Then, an improved closed-loop system based on the change of current in the full speed range is proposed. The experimental results show that the proposed control strategy can provide a highly accurate and robust sensorless operation from near zero to 20 000 r/min.

Sensorless Low-Current Start-Up Strategy of 100-kW BLDC Motor With Small Inductance

This paper focuses on the start-up strategy of a high-speed 100-kW brushless dc motor with small inductance using a voltage comparator. This paper includes three key technique contributions: 1) determining zero-speed positioning, 2) removing high-frequency disturbances, and 3) optimizing the controller parameters. The sensorless low-current start-up strategy is based on an amplification circuit: a low-pass filter circuit and a signal modulate circuit. The amplification circuit is used to amplify the amplitude of back electromotive force for detecting the rotor position at low speed, the low-pass filter circuit is used to remove high-frequency disturbances, and the signal modulate circuit is used to obtain the rotor position signal. A hysteresis control strategy is proposed against the load disturbance in the start-up stage. Experimental results show that the proposed sensorless start-up strategy can realize a low-current start-up.

Design aspects of a large scale turbomolecular pump with active magnetic bearings

A large scale 5-axis magnetically levitated turbomolecular pump is designed and fabricated in this paper. The rotor is supported by two radial active magnetic bearings (AMBs) and an axial AMB, and driven by a high-speed brushless DC Motor with a ring permanent magnet. The considerations discussed are described by design of an actual magnetic levitation turbomolecular pump with rated high-speed vacuum pumping speed of 4100L/s and ultra-high vacuum of the order of 1.8 × 10−7Pa. The vacuum, stress, modal, and electromagnetic aspects are put equal weight in the design of a large scale turbomolecular pump supported by AMBs. The thermal assembly technology of the ring PM, sleeve, and shaft for the turbo rotor is proposed. Finally, the suggested design methodology for designing a large scale turbomolecular pump with AMBs is presented.

Fault-Tolerant Inverter for High-Speed Low-Inductance BLDC Drives in Aerospace Applications

Due to the simplicity and high reliability, brushless dc (BLDC) motors are widely used in space application. High-reliability levels are the vital aspect for ensuring the long-term stable operation of the BLDC motor system, which is used in aerospace applications. The fault-tolerant control of the BLDC motor is of great importance for its continuous operating capacity even under the faulty situation. This paper proposes a fault-tolerant topology composed of an additional phase leg and a fault-protective circuit for the high-speed low-inductance BLDC motor. Based on the analysis of the overcurrent and overvoltage phenomenon after the switch faults, a novel fault isolation and system reconfiguration method is presented. The method can achieve safe isolation and reconfiguration to avoid the secondary fault caused by direct switch of the redundant switch and the faulty switch after the fault-diagnosis process. Both simulation and experimental results confirm the feasibility and effectiveness of the proposed method.